Yes all four of the sensors are needed by the computer. If you mean that you are having a cat back system put on then there will be no issue since their mounting bungs will still be intact.
well........yeah- get headers with those O2 portals on 'em-
The O2 sensors make sure your engine is not running to rich or too lean. Your gas mileage will suffer without them.
Does a 1997 Mercury Grand Marquis Have a Block Heater?
1997 Mercury Grand Marquis 4 Dr LS Sedan
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General
1999 Mercury Grand Marquis with no owner manual. Radio/cassette has buttons marked cd/tape. When cd pressed display reads "no cddj". Does this button control optional cd changer. Should there be a con...
1999 Mercury Grand Marquis 4 Dr LS Sedan
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How to replace a Blend Door actuator on my 2006 Mercury Grand Marquis?
2006 Mercury Grand Marquis
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Did Mercury make a Grand Marquis without air conditioning? Can I buy a short belt and bypass the compressor?
2000 Mercury Grand Marquis GS
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I just bought a 2000 Grand Mercury Marquis I've change the cooling fan but it's not turning on the car is not overheating also I want to know why the fan is not turning on ?I want to know where is ...
2000 Mercury Grand Marquis LS
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Maintenance & Repair
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